Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b2fdebeb13849d…

MALICIOUS

PDF

76.8 KB Created: 2021-09-18 13:12:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 16eeb2b2adbad8f85c4285857c72c4de SHA-1: 2536849f2786b4285d77c852f6774629e73c96af SHA-256: 81b2fdebeb13849d73d35d670d4e47d1fb3eacba801df8b71f1ff390e7235437
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The ML classifier and ClamAV detection strongly indicate maliciousness. The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of multiple PDF-specific heuristics related to URI and link farms further supports this conclusion.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://allytemp.ru/uplcv?utm_term=tun+device+android PDF link annotation
    • http://uco-kampen.com/media/files/18503462825.pdfIn PDF document text
    • https://gccpay.net/wp-content/plugins/super-forms/uploads/php/files/2e5a9d0ea9ebc22ffa37601ee281279b/bukataforonekoxaw.pdfIn PDF document text
    • http://www.prctech-th.com/ckfinder/userfiles/files/mamovutaz.pdfIn PDF document text
    • https://ihotel2b.com/upfiles/editor/files/kopuwup.pdfIn PDF document text
    • http://sys-svinding.dk/userfiles/file/tudazomafowoluson.pdfIn PDF document text
    • http://sattosushi.com/uploads/files/ganomutugonidafudiwoke.pdfIn PDF document text
    • https://rts-wm.com/ckfinder/userfiles/files/mujuz.pdfIn PDF document text
    • https://femagnet.com/upload/edu/article/file/jufijuwirebamotefifubu.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1612ece79691b4---bemozelusosujosokalogun.pdfIn PDF document text
    • http://lecostationery.com/files/file/jisotupodusagipun.pdfIn PDF document text
    • https://aartipalette.com/userfiles/file/85058011354.pdfIn PDF document text
    • http://telecycling.info/files/file/zudagawiburu.pdfIn PDF document text
    • https://accounting789.com/ThImg/file/11745389058.pdfIn PDF document text
    • http://3duct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ecaa702155---pezekikewa.pdfIn PDF document text
    • https://atlas-consulting.ro/fckeditor/fisiere/file/70188754827.pdfIn PDF document text
    • https://himarco.ir/basefile/himarcoir/files/47426853938.pdfIn PDF document text
    • https://www.lindopoint.it/wp-content/plugins/super-forms/uploads/php/files/d1459fa754bf7185846e5d801de9e9bf/81967184302.pdfIn PDF document text
    • https://chambres-lannion.fr/userfiles/file/91101983677.pdfIn PDF document text
    • http://www.yourhealthyourchoice.org/wp-content/plugins/formcraft/file-upload/server/content/files/16144fcdb16563---82493168427.pdfIn PDF document text
    • http://knupress.com/pds/editor/file/79311044261.pdfIn PDF document text
    • http://reelproductionshd.com/userfiles/file/buzujepaxiduwizu.pdfIn PDF document text
    • http://avtosfera28.ru/userfiles/file/lulatugoxexikafodirofenas.pdfIn PDF document text
    • https://ewdel.cz/ckfinder/userfiles/files/61596307632.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c95e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC95E 17420 bytes
SHA-256: 9925b2db7c2e51befe1b57c6bc2695a43ee1bce98c53d1cf7220c4d86093f94f
font_01_sfnt_off0000f677.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF677 10180 bytes
SHA-256: 246eae6c4ace635794253ea8ad9b9961350747d81be868e3d360881cb69539eb
font_02_sfnt_off00010d5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D5E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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